Catheter for delivery of energy to a surgical site

ABSTRACT

A catheter for delivering energy to a surgical site is disclosed. The catheter includes at a proximal end a handle and at a distal end a probe. The catheter includes at least one energy delivery device and an activation element. The at least one energy delivery device is located at the distal end of the catheter to deliver energy to portions of the surgical site. The activation element is located at the distal end of the catheter, to transition the probe from a linear to a multi-dimensional shape, within the surgical site. Methods for deploying the probe from the linear to multi-dimensional shape are disclosed.  
     In another embodiment of the invention the catheter includes a heating element fabricated on a substrate by photo-etching to deliver thermal energy to portions of the surgical site. In another embodiment of the invention the catheter includes an energy delivery element, a tip and a blade. The energy delivery element is located at the distal end of the catheter to deliver energy to portions of the intervertebral disc. The blade is positioned within a first lumen of the tip and is extensible beyond the tip, to cut selected portions within the intervertebral disc. In another embodiment of the invention a catheter includes both energy and material transfer elements and an interface on the handle thereof The interface couples the energy delivery element and the material transfer element to external devices for energy and material transfer to and from the intervertebral disc.

REFERENCE TO CO-PENDING APPLICATIONS

[0001] This application is a continuation in part of provisionalapplication serial No. 60/078,545 filed on Mar. 19, 1998 and entitled“Catheter for delivery of energy to a tissue” which is herebyincorporated by reference as if fully set forth herein.

BACKGROUND

[0002] 1. Field of the Invention

[0003] This invention relates to methods and apparatuses to treatintervertebral disc problems and/or for modifying intervertebral disctissue. More particularly this invention relates to percutaneoustechniques to avoid major surgical intervention. In one embodiment,annular fissures are treated by radio frequency (RF) heating ofintervertebral disc tissue.

[0004] 2. Description of Related Art

[0005] Intervertebral disc abnormalities (e.g., morphologic) have a highincidence in the population and may result in pain and discomfort ifthey impinge on or irritate nerves. Disc abnormalities may be the resultof trauma, repetitive use, metabolic disorders and the aging process andinclude such disorders but are not limited to degenerative discs (i)localized tears or fissures in the annulus fibrosus, (ii) localized discherniations with contained or escaped extrusions, and (iii) chronic,circumferential bulging disc.

[0006] Disc fissures occur rather easily after structural degeneration(a part of the aging process that may be accelerated by trauma) offibrous components of the annulus fibrosus. Sneezing, bending or justattrition can tear these degenerated annulus fibers, creating a fissure.The fissure may or may not be accompanied by extrusion of nucleuspulposus material into or beyond the annulus fibrosus. The fissureitself may be the sole morphological change, above and beyondgeneralized degenerative changes in the connective tissue of the disc.Even if there is no visible extrusion, biochemicals within the disc maystill irritate surrounding structures. Disc fissures can bedebilitatingly painful. Initial treatment is symptomatic, including bedrest, pain killers and muscle relaxants. More recently spinal fusionwith cages has been performed when conservative treatment did notrelieve the pain. The fissure may also be associated with a herniationof that portion of the annulus.

[0007] With a contained disc herniation, there are no free nucleusfragments in the spinal canal. Nevertheless, even a contained discherniation is problematic because the outward protrusion can press onthe spinal nerves or irritate other structures. In addition to nerveroot compression, escaped nucleus pulposus contents may chemicallyirritate neural structures. Current treatment methods include reductionof pressure on the annulus by removing some of the interior nucleuspulposus material by percutaneous nuclectomy. However, complicationsinclude disc space infection, nerve root injury, hematoma formation,instability of the adjacent vertebrae and collapse of the disc fromdecrease in height.

[0008] Another disc problem occurs when the disc bulges outwardcircumferentially in all directions and not just in one location. Overtime, the disc weakens and takes on a “roll” shape or circumferentialbulge. Mechanical stiffness of the joint is reduced and the joint maybecome unstable. One vertebra may settle on top of another. This problemcontinues as the body ages, and accounts for shortened stature in oldage. With the increasing life expectancy of the population, suchdegenerative disc disease and impairment of nerve function are becomingmajor public health problems. As the disc “roll” extends beyond thenormal circumference, the disc height may be compromised, and foraminawith nerve roots are compressed. In addition, osteophytes may form onthe outer surface of the disc roll and further encroach on the spinalcanal and foramina through which nerves pass. This condition is calledlumbar spondylosis.

[0009] It has been thought that such disc degeneration creates segmentalinstability which disturbs sensitive structures which in turn registerpain. Traditional, conservative methods of treatment include bed rest,pain medication, physical therapy or steroid injection. Upon failure ofconservative therapy, spinal pain (assumed to be due to instability) hasbeen treated by spinal fusion, with or without instrumentation, whichcauses the vertebrae above and below the disc to grow solidly togetherand form a single, solid piece of bone. The procedure is carried outwith or without discectomy. Other treatments include discectomy alone ordisc decompression with or without fusion.

[0010] Nuclectomy can be performed by removing some of the nucleus toreduce pressure on the annulus. However, complications include discspace infection, nerve root injury, hematoma formation, and instabilityof adjacent vertebrae.

[0011] These interventions have been problematic in that alleviation ofback pain is unpredictable even if surgery appears successful. Inattempts to overcome these difficulties, new fixation devices have beenintroduced to the market, including but not limited to pedicle screwsand interbody fusion cages. Although pedicle screws provide a highfusion success rate, there is still no direct correlation between fusionsuccess and patient improvement in function and pain. Studies on fusionhave demonstrated success rates of between 50% and 67% for painimprovement, and a significant number of patients have more painpostoperatively. Therefore, different methods of helping patients withdegenerative disc problems need to be explored.

[0012]FIGS. 1A and 1B illustrate a cross-sectional anatomical view of avertebra and associated disc and a lateral view of a portion of a lumbarand thoracic spine, respectively. Structures of a typical cervicalvertebra (superior aspect) are shown in FIG. 1A: 104—lamina; 106—spinalcord; 108—dorsal root of spinal nerve; 114—ventral root of spinal nerve;116—posterior longitudinal ligament; 118—intervertebral disc;120—nucleus pulposus; 122—annulus fibrosus; 124—anterior longitudinalligament; 126—vertebral body; 128—pedicle; 130—vertebral artery;132—vertebral veins; 134—superior articular facet; 136—posterior lateralportion of the annulus; 138—posterior medial portion of the annulus; and142—spinous process. In FIG. 1A, one side of the intervertebral disc 118is not shown so that the anterior vertebral body 126 can be seen. FIG.1B is a lateral aspect of the lower portion of a typical spinal columnshowing the entire lumbar region and part of the thoracic region anddisplaying the following structures: 118—intervertebral disc;126—vertebral body; 142—spinous process; 170—inferior vertebral notch;172—spinal nerve; 174—superior articular process; 176—lumbar curvature;and 180—sacrum.

[0013] The presence of the spinal cord (nerve sac) and the posteriorportion of the vertebral body 126, including the spinous process 142,and superior and inferior articular processes 110, prohibit introductionof a needle or trocar from a directly posterior position. This isimportant because the posterior disc wall is the site of symptomaticannulus tears and disc protrusions/extrusions that compress or irritatespinal nerves for most degenerative disc syndromes. The inferiorarticular process, along with the pedicle 128 the lumbar spinal nerve,form a small “triangular” window 168 (shown in black in FIG. 1C) throughwhich introduction can be achieved from the posterior lateral approach.FIG. 1D looks down on an instrument introduced by the posterior lateralapproach. It is well known to those skilled in the art that percutaneousaccess to the disc is achieved by placing an introducer into the discfrom this posterior lateral approach, but the triangular window does notallow much room to maneuver. Once the introducer pierces the toughannulus fibrosus, the introducer is fixed at two points along its lengthand has very little freedom of movement. Thus, this approach has allowedaccess only to small central and anterior portions of the nucleuspulposus. Current methods do not permit percutaneous access to theposterior half of the nucleus or to the posterior wall of the disc.Major and potentially dangerous surgery is required to access theseareas.

[0014] U.S. Pat. No. 5,433,739 (the “739 patent”) discloses placement ofan RF electrode in an interior region of the disc approximately at thecenter of the disc. RF power is applied, and heat then putativelyspreads out globally throughout the disc. The ′739 patent teaches theuse of a rigid shaft which includes a sharpened distal end thatpenetrates through the annulus fibrosus and into the nucleus pulposus.In one embodiment the shaft has to be rigid enough to permit the distalend of the RF electrode to pierce the annulus fibrosus, and the abilityto maneuver its distal end within the nucleus pulposus is limited. Inanother embodiment, a somewhat more flexible shaft is disclosed.However, neither embodiment of the devices of the ′739 patent permitsaccess to the posterior, posterior lateral and posterior medial regionof the disc, nor do they provide for focal delivery of therapy to aselected local region within the disc or precise temperature control atthe annulus. The ′739 patent teaches the relief of pain by globallyheating the disc. There is no disclosure of treating an annular tear orfissure.

[0015] U.S. Pat. No. 5,201,729 (the “′729 patent”) discloses the use ofan optical fiber that is introduced into a nucleus pulposus. In the ′729patent, the distal end of a stiff optical fiber shaft extends in alateral direction relative to a longitudinal axis of an introducer. Thisprevents delivery of coherent energy into the nucleus pulposus in thedirection of the longitudinal axis of the introducer. Due to theconstrained access from the posterior lateral approach, stiff shaft andlateral energy delivery, the device of the ′729 patent is unable to gainclose proximity to selected portion(s) of the annulus (i.e., posteriormedial and central posterior) requiring treatment or to preciselycontrol the temperature at the annulus. No use in treating an annularfissure is disclosed.

BRIEF DESCRIPTION OF THE DRAWINGS

[0016] A clear conception of the advantages and features constitutingthe present invention, and of the components and operation of modelsystems provided with the present invention, will become more readilyapparent by referring to the exemplary, and therefore nonlimiting,embodiments illustrated in the drawings accompanying and forming a partof this specification, wherein like reference numerals (if they occur inmore than one view) designate the same elements. It should be noted thatthe features illustrated in the drawings are not necessarily drawn toscale.

[0017]FIG. 1A is a superior cross-sectional anatomical view of acervical disc and vertebra.

[0018]FIG. 1B is a lateral anatomical view of a portion of a lumbarspine.

[0019]FIG. 1C is a posterior-lateral anatomical view of two lumbarvertebrae and an illustration of the triangular working zone,representing an embodiment of the present invention.

[0020]FIG. 1D is a superior cross-sectional view of the requiredposterior FIG. 2A is a plan view of an introducer and an instrument ofthe invention in which solid lines illustrate the position of theinstrument in the absence of bending forces and dotted lines indicatethe position the distal portion of the instrument would assume underbending forces applied to the intradiscal section of the instrument,representing an embodiment of the present invention.

[0021]FIG. 2B is an end view of the handle of the embodiment shown inFIG. 2A.

[0022]FIG. 3 is a side view of a catheter with a elastically deformedend section with an arcuate shape.

[0023] FIGS. 4A-D show the surgical steps connected with the insertionof the catheter of FIG. 3 into a surgical site. FIG. 5 is a side view ofa catheter with a elastically deformed end section with an inward spiralshape.

[0024]FIG. 6A-6B is a side view of a catheter with a elasticallydeformed end section with an outward spiral shape.

[0025]FIG. 7 is a side view of a catheter with a elastically deformedend section with an “eggbeater” shape.

[0026] FIGS. 8A-F are isometric views of an alternate embodiment of theinvention in which the probe of the catheter performs an electrophoreticfunction.

[0027] FIGS. 9A-D show the surgical steps connected with the insertionof the catheter of FIGS. 7-8 into a surgical site.

[0028] FIGS. 10A-B show catheters with thermal energy delivery sources.

[0029]FIG. 11 shows a thermal delivery element for a catheter.

[0030] FIGS. 12 A-C show a catheter probe with a knife, lumen, andenergy delivery element.

[0031]FIG. 13 shows a catheter connector including fluid deliverycoupling.

[0032]FIG. 14 shows another connector with fluid delivery coupling.

SUMMARY OF THE INVENTION

[0033] Accordingly, it is desirable to diagnose and treat discabnormalities such as disc degeneration at locations previously notaccessible via percutaneous approaches and without major surgicalintervention or substantial destruction to the disc. It would be furtherdesirable to treat disc abnormalities via controlled high-energy inputavailable through radio frequency energy. It would be further desirableto provide such RF energy to the nucleus pulposus at the posterior,posterior lateral and the posterior medial regions of the inner wall ofthe annulus fibrosis, without heating other regions of the nucleus, aswould occur with prior art heating elements. It would further bedesirable to be able to administer materials to, or remove materialsfrom, a precise, selected location within the disc, particularly to thelocation of the annular fissure. It would be further desirable toprovide thermal energy into collagen in the area of the fissure tostrengthen the annulus and possibly fuse collagen to the sides of thefissure, particularly at the posterior, posterior lateral and theposterior medial regions of the inner wall of the annulus fibrosus.

[0034] A primary object of the invention is to provide a minimallyinvasive method and apparatus for diagnosing and treating fissures ofdiscs at selected locations within the disc.

[0035] Another object of the invention is to provide a minimallyinvasive method and apparatus for treating morphological abnormalitiesof discs at selected locations within the disc via radio frequencyelectrodes.

[0036] Another object of the invention is to provide a device which hasa distal end that is inserted into the disc and accesses the posterior,posterior lateral and the posterior medial regions of the inner wall ofthe annulus fibrosis for application of RF energy at such location.

[0037] Another object of the invention is to provide an apparatus whichis advanceable and navigable at the inner wall of the annulus fibrosusto provide localized heating at the site of the annular fissure.

[0038] Another object of the invention include providing apparatus andmethods for diagnosing an abnormality and/or adding or removing amaterial at a preselected location of a disc via a functional element.

[0039] Another object of the invention is to provide a device which hasa distal end that is inserted into the disc and accesses the posterior,posterior lateral and the posterior medial of the inner wall of theannulus fibrosus in order to repair or shrink an annular fissure at sucha location.

[0040] Another object of the invention is to provide a non-destructivemethod and apparatus for treating morphologic abnormalities of discs.

[0041] Another object of the invention is to provide a method andapparatus to treat degenerative intervertebral discs by deliveringthermal energy to denervate selective nerves embedded in the walls ofthe disc.

[0042] Another objective of the invention is to provide a method andapparatus to treat degenerative intervertebral discs by deliveringthermal energy to cauterize granulation tissue that is ingrown in thewall of the disc.

[0043] Another object of the invention is to provide a method andapparatus to treat degenerative intervertebral discs by deliveringthermal energy to break down selected enzyme systems andneurotransmitters that generate pain within the disc.

[0044] Another object of the invention is to provide a method andapparatus to treat degenerative intervertebral discs by shrinking aselected amount of collagen in the annulus fibrosis of the disc andremove a redundancy in the disc roll.

[0045] Another object of the invention is to provide a method andapparatus to treat degenerative intervertebral discs by deliveringthermal energy to at least a portion of the nucleus pulposus to reducewater content of the nucleus pulposus and shrink the nucleus pulposuswithout creating a contained herniated disc.

[0046] Another object of the invention is to provide a method andapparatus to treat degenerative intervertebral discs by supplyingsufficient thermal energy to shrink the nucleus pulposus and tighten thedisc.

[0047] Another object of the invention is to provide an apparatus totreat degenerative intervertebral discs which is advanceable andnavigational adjacent to an inner wall of the annulus fibrosis.

[0048] Another object of the invention is to provide a thermal energydelivery device which has a distal end that is inserted into the nucleuspulposus and accesses the posterior, posterior lateral and the posteriorcentral regions of the inner wall of the nucleus fibrosis.

[0049] The invention provides an intervertebral disc apparatus thatincludes an introducer with an introducer lumen and a catheter. Thecatheter is at least partially positioned in the introducer lumen andincludes an probe section and an energy delivery device coupled tointradiscal section. The intradiscal section is configured to beadvanceable through a nucleus pulposus of the intervertebral disc andpositionable adjacent to a selected site of an inner wall of an annulusfibrosis. The energy delivery device is configured to deliver sufficientenergy to heat at least a portion of the intervertebral disc withoutsubstantially removing intervertebral disc material positioned adjacentto the energy delivery device.

[0050] The invention also includes providing an externally guidableintervertebral disc apparatus for manipulation of disc tissue present ata preselected location of an intervertebral disc, the disc having anucleus pulposus, an annulus fibrosis, and an inner wall of the annulusfibrosis, the nucleus pulposus having a first diameter and a discplaying between opposing sections of the inner wall, proximity to thenucleus being provided by an introducer comprising an internalintroducer lumen with an opening at a terminus of the introducer,comprising a catheter having a distal end and a proximal end having alongitudinal access, the catheter being adapted to slidably advancethrough the introducer lumen, the catheter having an intradiscal sectionat the distal end of the catheter, the intradiscal section beingextendable through the opening of the introducer and having sufficientrigidity to be advanceable through the nucleus pulposus of the disc andaround the inner wall of the annulus fibrosis under a force appliedlongitudinally to the proximal end and having insufficient penetrationability to be advanceable through the inner wall of the annulus fibrosisunder the force; and a heating element located at the intradiscalsection selected from the group consisting of RF heating elements,resistive heating elements, chemical heating elements, and ultrasoundheating elements.

[0051] In an embodiment of the invention is based on a catheter fordelivering energy to a surgical site. The catheter includes at aproximal end a handle and at a distal end a probe. The catheter includesat least one energy delivery device and an activation element. The atleast one energy delivery device is located at the distal end of thecatheter to deliver energy to portions of the surgical site. Theactivation element is located at the distal end of the catheter, totransition the probe from a linear to a multi-dimensional shape, withinthe surgical site. In another embodiment of the invention the catheterincludes a substrate and a heating element. The substrate is located atthe distal end of the catheter. The heating element is fabricated on thesubstrate by photo-etching to deliver thermal energy to portions of thesurgical site.

[0052] In another embodiment of the invention the catheter includes afirst probe section, at least one energy delivery element, a tip and ablade. The first probe section defines along a length thereof a firstlumen. The at least one energy delivery element is located at the distalend of the catheter to deliver energy to portions of the intervertebraldisc. The tip is coupled to the first probe section at a terminusthereof. The tip defines on an exterior face a second lumensubstantially concentric with said first lumen. The blade is positionedwithin the first lumen and is extensible from a first position withinsaid first probe section, to a second position extending through thesecond lumen and beyond the tip, to cut selected portions within theintervertebral disc.

[0053] In another embodiment of the invention a catheter includes anenergy delivery element, a material transfer element, and at least oneinterface on the handle thereof. The energy delivery element is locatedat the distal end of the catheter to deliver energy to portions of theintervertebral disc. The material transfer element is located at thedistal end of the catheter to transfer material to and from theintervertebral disc. The at least one interface on the handle couplesthe energy delivery element and the material transfer element toexternal devices for energy and material transfer to and from theintervertebral disc.

[0054] In still another embodiment of the invention a method fordeploying a probe portion of a catheter in a multi-dimensional shapewithin a surgical site is disclosed. The method includes the steps of:configuring the probe of the catheter in a substantially linearconfiguration; applying a sufficient force to advance the probe of thecatheter through the nucleus pulposus, which force is insufficient topuncture the annulus fibrosus; deploying the probe in a substantiallyarcuate configuration within the inner wall of the annulus fibrosus, anddelivering energy from the probe to portions of the intervertebral disc.

[0055] In another embodiment of the invention a catheter for treating anintervertebral disc is disclosed. The catheter includes anelectrophoretic element located at the distal end of the catheter toalter the milieu within the intervertebral disc.

DETAILED DESCRIPTION

[0056] The present invention provides a method and apparatus fortreating intervertebral disc disorders by the application of controlledheating to a localized region of an intervertebral disc. Such disordersinclude but are not limited to (i) degenerative discs which have tearsor fissures in the annulus fibrosis, particularly fissures of theannulus fibrosis, which may or may not be accompanied with contained orescaped extrusions, (ii) contained disc herniations with focalprotrusions, and (iii) bulging discs. Such disorders include but are notlimited to (i) degenerative discs which have tears or fissures in theannulus fibrosis, (ii) contained disc herniations with focalprotrusions, and (iii) bulging discs.

[0057] Degenerative discs with tears or fissures are treatednon-destructively without the removal of disc tissue other than limitedablation to the nucleus pulposus which changes some of the water contentof the nucleus pulposus. Nothing is added to supplement the mechanics ofthe disc. Electromagnetic energy is delivered to a selected section ofthe disc in an amount which does not create a destructive lesion to thedisc, other than at most a change in the water content of the nucleuspulposus. In one embodiment, there is no removal and/or vaporization ofdisc material positioned adjacent to an energy delivery devicepositioned in a nucleus pulposus. Sufficient electromechanical energy isdelivered to the disc to change its biochemical, neurophysiologic and/orbiomechanical properties. Neurophysiologic modifications includedenervation of nociceptores in a tear or fissure in the annulusfibrosis.

[0058] Degenerative intervertebral discs with fissures are treated bydenervating selected nerves that are embedded in the interior wall ofthe annulus fibrosis as well as nerves outside of the interior wallincluding those on the surface of the wall. Electromagnetic energy isused to cauterize granulation tissue which are pain sensitive areas andformed in the annulus fibrosis wall. Electromagnetic energy is also usedto break down selected enzyme systems and neurotransmitters thatgenerate pain within the disc. Generally, these enzymes andneurotransmitters only work within a small bandwidth of both pH andtemperature.

[0059] Electromagnetic energy is applied to shrink collagen in theannulus fibrosis and/or nucleus pulposus. This reduces the redundancy inthe disc roll that is created in a disc. Delivery of electromagneticenergy to the nucleus pulposus removes some water and permits thenucleus pulposus to withdraw. This reduces a “pushing out” effect thatcreated a contained herniation. Combinations of shrinking the disc,shrinking of the nucleus pulposus by reducing water content, as well astightening up the annulus fibrosis wall creates a rejuvenation of thedisc. Reducing the pressure in the disc and tightening the annulusfibrosis produces a favorable biomechanical effect. Application ofelectromagnetic energy locally increases the stiffness of the disc.

[0060] The annulus fibrosis is comprised primarily of fibrosis-likematerial and the nucleus pulposus is comprised primarily of an amorphouscolloidal gel. The distinction between the annulus fibrosis and thenucleus pulposus becomes more difficult to distinguish when a patient is30 years old or greater. There is often a transition zone between theannulus fibrosis and the nucleus pulposus made of fibrosis-like materialand amorphous colloidal gel. For purposes of this disclosure, the innerwall of the annulus fibrosis includes the young wall comprised primarilyof fibrosis-like material as well as the transition zone which includesboth fibrous-like material and amorphous colloidal gels (hereinaftercollectively referred to as “inner wall of the annulus fibrosis”).

[0061] In general, an apparatus of the invention is in the form of anexternally guidable intervertebral disc apparatus for accessing andmanipulating disc tissue present at a selected location of anintervertebral disc having a nucleus pulposus and an annulus fibrosus,the annulus having an inner wall. Use of a temperature-controlled energydelivery element, combined with the navigational control of theinventive catheter, provides preferential, localized heating to treatthe fissure. For ease of reference to various manipulations anddistances described below, the nucleus pulposus can be considered ashaving a given diameter in a disc plane between opposing sections of theinner wall. This nucleus pulposus diameter measurement allows instrumentsizes (and parts of instruments) designed for one size disc to bereadily converted to sizes suitable for an instrument designed for adifferent size of disc.

[0062] The operational portion of the apparatus of the invention isbrought to a location in or near the disc's fissure using techniques andapparatuses typical of percutaneous interventions. For convenience andto indicate that the apparatus of the invention can be used with anyinsertional apparatus that provides proximity to the disc, includingmany such insertional apparatuses known in the art, the term“introducer” is used to describe this aid to the method. An introducerhas an internal introducer lumen with a distal opening at a terminus ofthe introducer to allow insertion (and manipulation) of the operationalparts of the apparatus into (and in) the interior of a disc.

[0063] The operational part of the apparatus comprises an elongatedelement referred to as a catheter, various parts of which are located byreference to a distal end and a proximal end at opposite ends of itslongitudinal axis. The proximal end is the end closest to the externalenvironment surrounding the body being operated upon (which may still beinside the body in some embodiments if the catheter is attached to ahandle insertable into the introducer). The distal end of the catheteris intended to be located inside the disc under conditions of use. Thecatheter is not necessarily a traditional medical catheter (i.e., anelongate hollow tube for admission or removal of fluids from an internalbody cavity) but is a defined term for the purposes of thisspecification. “Catheter” has been selected as the operant word todescribe this part of the apparatus, as the inventive apparatus is along, flexible tube which transmits energy and/or material from alocation external to the body to a location internal to the disc beingaccessed upon, such as a collagen solution and heat to the annularfissure. Alternatively, material can be transported in the otherdirection to remove material from the disc, such as removing material byaspiration to decrease pressure which is keeping the fissure open andaggravating the symptoms due to the fissure.

[0064] The catheter is adapted to slidably advance through theintroducer lumen, the catheter having an probe section at the distal endof the catheter, the probe section being extendible through the distalopening at the terminus of the introducer into the disc. Although thelength of the probe portion can vary with the intended function asexplained in detail below, a typical distance of extension is at leastone-half the diameter of the nucleus pulposus, preferably in the rangeof one-half to one and one-half times the circumference of the nucleus.

[0065] In order that the functional elements of the catheter (e.g., anelectromagnetic probe, such as, an RF electrode or a resistance heater)can be readily guided to the desired location within a disc, the probeportion of the catheter is manufactured with sufficient rigidity toavoid collapsing upon itself while being advanced through the nucleuspulposus and navigated around the inner wall of the annulus fibrosus.The probe portion, however, has insufficient rigidity to puncture theannulus fibrosus under the same force used to the catheter through thenucleus pulposus and around the inner wall of the annulus fibrosus.Absolute penetration ability will vary with sharpness and stiffness ofthe tip of the catheter, but in all cases a catheter of the presentinvention will advance more readily through the nucleus pulposus thanthrough the annulus fibrosus.

[0066] In preferred embodiments, the probe section of the catheterfurther has differential bending ability in two orthogonal directions atright angles to the longitudinal axis. This causes the catheter to bendalong a desired plane (instead of at random). Also when a torsional(twisting) force is applied to the proximal end of the catheter tore-orient the distal end of the catheter, controlled advancement of thecatheter in the desired plane is possible.

[0067] A further component of the catheter is a functional elementlocated in the probe section for diagnosis or for adding energy andadding and/or removing material at the selected location of the discwhere the annular tear is to be treated. The apparatus allows thefunctional element to be controllably guided by manipulation of theproximal end of the catheter into a selected location for localizedtreatment of the annular fissure.

[0068] The method of the invention, which involves manipulating disctissue at the annular fissure, is easily carried out with an apparatusof the invention. An introducer is provided that is located in apatient's body so that its proximal end is external to the body and thedistal opening of its lumen is internal to the body and (1) internal tothe annulus fibrosus or (2) adjacent to an annular opening leading tothe nucleus pulposus, such as an annular tear or trocar puncture thatcommunicates with the nucleus pulposus. The catheter is then slid intoposition in and through the introducer lumen so that the functionalelement in the catheter is positioned at the selected location of thedisc by advancing or retracting the catheter in the introducer lumen andoptionally twisting the proximal end of the catheter to preciselynavigate the catheter. By careful selection of the rigidity of thecatheter and by making it sufficiently blunt to not penetrate theannulus fibrosus, and by careful selection of the flexibility in oneplane versus the orthogonal plane, the distal portion of the catheterwill curve along the inner wall of the annulus fibrosus as it isnavigated and is selectively guided to an annular tear at selectedlocation(s) in the disc. Energy is applied and/or material is added orremoved at the selected location of the disc via the functional element.of the elements of the apparatus and method will now be described inmore detail. However, a brief description of disc anatomy is providedfirst, as sizes and orientation of structural elements of the apparatusand operations of the method can be better understood in some cases byreference to disc anatomy.

[0069] An Exemplary Surgical Site

[0070] The annulus fibrosus is comprised primarily of tough fibrousmaterial, while the nucleus pulposus is comprised primarily of anamorphous colloidal gel. There is a transition zone between the annulusfibrosus and the nucleus pulposus made of both fibrous-like material andamorphous colloidal gel. The border between the annulus fibrosus and thenucleus pulposus becomes more difficult to distinguish as a patientages, due to degenerative changes. This process may begin as early as 30years of age. For purposes of this specification, the inner wall of theannulus fibrosus can include the young wall comprised primarily offibrous material as well as the transition zone which includes bothfibrous material and amorphous colloidal gels (hereafter collectivelyreferred to as the “inner wall of the annulus fibrosus”). Functionally,that location at which there is an increase in resistance to catheterpenetration and which is sufficient to cause bending of the distalportion of the catheter into a radius less than that of the internalwall of the annulus fibrosus is considered to be the “inner wall of theannulus fibrosus.” As with any medical instrument and method, not allpatients can be treated, especially when their disease or injury is toosevere. There is a medical gradation of degenerative disc disease(stages 1-5). See, for example, Adams et al., “The Stages of DiscDegeneration as Revealed by Discograrns,” J. Bone and Joint Surgery, 68,36-41 (1986). As these grades are commonly understood, the methods ofinstrument navigation described herein would probably not be able todistinguish between the nucleus and the annulus in degenerative diseaseof grade 5. In any case, most treatment is expected to be performed indiscs in stages 3 and 4, as stages 1 and 2 are asymptomatic in mostpatients, and stage 5 may require disc removal and fusion.

[0071] Some of the following discussion refers to motion of the catheterinside the disc by use of the terms “disc plane,” “oblique plane” and“cephalo-caudal plane.” These specific terms refer to orientations ofthe catheter within the intervertebral disc. now to the figures, FIGS.2A and 2B illustrate one embodiment of a catheter 200 of the inventionas it would appear inserted into the lumen 214 of an introducer 210. Theapparatus shown is not to scale, as an exemplary apparatus (as will beclear from the device dimensions below) would be relatively longer andthinner; the proportions used in FIG. 2A were selected for easierviewing by the reader. The catheter 200 includes handle 206, stem 208,probe section 216 and a tip 220. The handle 206 at the proximal end ofthe catheter is coupled via the stem 208 to the probe section 216, whichis located proximate the distal end of the device. At the terminus ofthe probe, i.e., the distal end of the device, is the tip 220. The tipmay be axially displaced from the probe section. Functional elements 222for delivery or energy or material to or from the site may be placedwithin the probe. These may, via connections within the probe, stem andhandle, be coupled to either an energy delivery device 202 or a materialtransfer device 204. Therefore no limitation should be placed on thetypes of energy, force, or material transporting elements present in thecatheter. These are merely some of the possible alternative functionalelements that can be included in the probe portion of the catheter. Theflexible, movable catheter 200 is at least partially positionable in theintroducer lumen 214, to bring the probe section, which is designed tobe the portion of the catheter that will be pushed out of the introducerlumen and into the nucleus pulposus and into the selected location(s)with regard to the annular tear. Dashed lines are used to illustratebending of the probe portion of the catheter as it might appear underuse, as discussed in detail later in the specification.

[0072]FIG. 2B shows an axial cross-section of stem 208 at the proximalend of the catheter. In this embodiment of the invention the stem has anoval shape, as does the lumen 214 thus allowing the rotationalorientation of the probe to be fixed with respect to the introducer.Other sections and properties of catheter 200 are described later.

[0073] For one embodiment suitable for intervertebral discs, the outerdiameter of catheter 200 is in the range of 0.2 to 5 mm, the totallength of catheter 200 (including the portion inside the introducer) isin the range of 10 to 60 cm, and the length of introducer 210 is in therange of 5 to 50 cm. For one preferred embodiment, the catheter has adiameter of 1 mm, an overall length of 30 cm, and an introduced lengthof 15 cm (for the probe section). With an instrument of this size, aphysician can insert the catheter for a distance sufficient to reachselected location(s) in the nucleus of a human intervertebral disc.

[0074] Any device in which bending of the tip of a catheter of theinvention is at least partially controlled by the physician is “activelysteerable.” A mandrel may facilitate the active steering of a catheter.

[0075] Active Steering of Catheter

[0076] Referring now to FIG. 2B, a guiding mandrel 232 can be includedboth to add rigidity to the catheter and to inhibit movement of probesection 216 of the catheter 200 along an inferior axis 242 whileallowing it along a superior axis 240 while positioned and aligned inthe disc plane of a nucleus pulposus 120. This aids the functions ofpreventing undesired contact with a vertebra and facilitatingnavigation. The mandrel can be flattened to encourage bending in a plane(the “plane of the bend”) orthogonal to the “flat” side of the mandrel.“Flat” here is a relative term, as the mandrel can have a D-shapedcross-section, or even an oval or other cross-sectional shape without aplanar face on any part of the structure. Regardless of the exactconfiguration, bending will preferentially occur in the plane formed bythe principal longitudinal axis of the mandrel and a line connecting theopposite sides of the shortest cross-sectional dimension of the mandrel(the “thin” dimension). To provide sufficient resistance to the catheterbending out of the desired plane while encouraging bending in thedesired plane, the minimum ratio is 1.25:1 (“thickest” to “thinnest”cross-sectional dimensions along at least a portion of the probesection). The maximum ratio is 20:1, with the preferred ratio beingbetween 1.5:1 and 16:3, more preferably between 2:1 and 3.5:1. Theseratios are for a solid mandrel and apply to any material, as deflectionunder stress for uniform solids is inversely proportional to thethickness of the solid in the direction (dimension) in which bending istaking place. For other types of mandrels (e.g., hollow or non-uniformmaterials), selection of dimensions and/or materials that provide thesame relative bending motions under stress are preferred.

[0077] A catheter of the present invention is designed with sufficienttorsional strength (resistance to twisting) to prevent undesireddirectional movement of the catheter. Mandrels formed from materialshaving tensile strengths in the range set forth in the examples of thisspecification provide a portion of the desired torsional strength. Othermaterials can be substituted so long as they provide the operationalfunctions described in the examples and desired operating parameters.

[0078] While the mandrel can provide a significant portion of the columnstrength, selective flexibility, and torsional strength of a catheter,other structural elements of the catheter also contribute to thesecharacteristics. Accordingly, it must be kept in mind that it is thecharacteristics of the overall catheter that determine suitability of aparticular catheter for use in the methods of the invention. Similarly,components inside the catheter, such as a heating element or pottingcompound, can be used to strengthen the catheter or provide directionalflexibility at the locations of these elements along the catheter.

[0079] It is not necessary that the guiding mandrel 232 be flattenedalong its entire length. Different mandrels can be designed fordifferent sized discs, both because of variations in disc sizes fromindividual to individual and because of variations in size from disc todisc in one patient. The bendable portion of the mandrel is preferablysufficient to allow probe section 216 of the catheter to navigate atleast partially around the circumference of the inner wall of theannulus fibrosus (so that the operational functions of the catheter canbe carried out at desired location(s) along the inner wall of theannulus fibrosus). Shorter bendable sections are acceptable forspecialized instruments. In most cases, a flattened distal portion ofthe mandrel of at least 10 mm, preferably 25 mm, is satisfactory. Theflattened portion can extend as much as the entire length of themandrel, with some embodiments being flattened for less than 15 cm, inother cases for less than 10 cm, of the distal end of the guide mandrel.

[0080] In preferred embodiments, the guide mandrel or other differentialbending control element is maintained in a readily determinableorientation by a control element located at the proximal end of thecatheter. The orientation of the direction of bending and its amount canbe readily observed and controlled by the physician. One possiblecontrol element is simply a portion of the mandrel that extends out ofthe proximal end of the introducer and can be grasped by the physician,with a shape being provided that enables the physician to determine theorientation of the distal portion by orientation of the portion in thehand. For example, a flattened shape can be provided that mimics theshape at the distal end (optionally made larger to allow better controlin the gloved hand of the physician, as in the handle 206 of FIG. 2A).More complex proximal control elements capable of grasping the proximalend of the mandrel or other bending control element can used if desired,including but not limited to electronic, mechanical, and hydrauliccontrols for actuation by the physician.

[0081] The guide mandrel can also provide the function of differentialflexibility by varying the thickness in one or more dimensions (forexample, the “thin” dimension, the “thick” dimension, or both) along thelength of the mandrel. A guide mandrel that tapers (becomes graduallythinner) toward the distal tip of the mandrel will be more flexible andeasier to bend at the tip than it is at other locations along themandrel. A guide mandrel that has a thicker or more rounded tip thanmore proximal portions of the mandrel will resist bending at the tip butaid bending at more proximal locations. Thickening (or thinning) canalso occur in other locations along the mandrel. Control of thedirection of bending can be accomplished by making the mandrel moreround, i.e., closer to having 1:1 diameter ratios; flatter in differentsections of the mandrel; or by varying the absolute dimensions(increasing or decreasing the diameter). Such control over flexibilityallows instruments to be designed that minimize bending in some desiredlocations (such as the location of connector of an electrical element toavoid disruption of the connection) while encouraging bending in otherlocations (e.g., between sensitive functional elements). In this manner,a catheter that is uniformly flexible along its entire length, isvariably flexibility along its entire length, or has alternating moreflexible and less flexible segment(s), is readily obtained simply bymanufacturing the guide mandrel with appropriate thickness at differentdistances and in different orientations along the length of the mandrel.Such a catheter will have two or more different radii of curvature indifferent segments of the catheter under the same bending force.

[0082] In some preferred embodiments, the most distal 3 to 40 mm of aguide mandrel is thinner relative to central portions of the probesection to provide greater flexibility, with the proximal 10 to 40 mm ofthe probe section being thicker and less flexible to add column strengthand facilitate navigation.

[0083] The actual dimensions of the guide mandrel will vary with thestiffness and tensile strength of the material used to form the mandrel.In most cases the mandrel will be formed from a metal (elemental or analloy) or plastic that will be selected so that the resulting catheterwill have characteristics of stiffness and bending that fall within thestated limits. Additional examples of ways to vary the stiffness andtensile strength include transverse breaks in a material, advance of thematerial so that it “doubles up,” additional layers of the same ordifferent material, tensioning or relaxing tension on the catheter, andapplying electricity to a memory metal.

[0084] Multi-dimensional Probe Deployment

[0085] Catheters which are actively steerable, may include additionallythe capability of deploying into planar substantially two dimensionalshapes or three dimensional shapes which conform to the surgical site.These multi-dimensional deployment capabilities, reduce operating time,improve operational accuracy and increase the utility of surgicalintervention.

[0086] Linear to Arcuate Transition of Probe

[0087] The following FIGS. 3-9 show apparatus and methods fortransitioning a probe from a linear to a multi-dimensional shape. Thetransition of the probe from a linear to an arcuate shape may be broughtabout by any of a group of activation elements including, but notlimited to, the following.

[0088] In an embodiment of the invention the probe may include aresilient material, e.g. a heat treated metal or spring metal, whichwill assume a linear shape only by virtue of the guiding force of thelumen portion of the introducer and will resume its original arcuateshape, upon introduction to the surgical site and by extension beyondthe confines of the introducer. The resilient spring-like material isarcuate in the absence of external stress but, under selected stressconditions (for example, while the catheter is inside the introducer),is linear. Such a biased distal portion can be manufactured from eitherspring metal or superelastic memory material (such as Tinel®nickel-titanium alloy, Raychem Corp., Menlo Park Calif.). The introducer(at least in the case of a spring-like material for forming thecatheter) is sufficiently strong to resist the bending action of thebent tip and maintain the biased distal portion in alignment as itpasses through the introducer. Compared to unbiased catheters, acatheter with a biased probe encourages advancement of the probesubstantially in the direction of the bend relative to other lateraldirections. Biasing the catheter tip also further decreases likelihoodthat the tip will be forced through the annulus fibrosus under thepressure used to advance the catheter. In those utilizing a resilientmaterial an introducer in combination with the resilient material isnecessary in order to introduce the probe in a linear or lay flatconfiguration to the surgical site.

[0089] Although an introducer may also be used with any of the followingactivation elements it is not necessary to bring about the transitionfrom a linear to an arcuate shape.

[0090] In another embodiment of the invention the probe may at least twomaterials with a different coefficient of thermal expansion joined toone another along their length, such that at one temperature, e.g. roomtemperature they are linear while at an elevated temperature, thedifferential expansion of one with respect to the other induces anarcuate bending of both. Bi-metallic strips such as copper and steelmight serve this function. Any other two metals with differentcoefficients of expansion could be substituted for copper and steel. Thegreater the differential of the coefficients of expansion between thetwo metals the smaller the radius(s) of the arcuate shape formed therebyat any given temperature differential. Other materials besides metalswith different coefficients of expansion could also be used. Thetemperature differential of the at least two materials at roomtemperature and at the surgical site may be increased by energydelivered to the probe, e. g. RF or resistive heating. Alternately,electrical power may be directly applied directly to one or both of theat least two materials provided they are electrically resistive suchthat the application of power will result in heat generation.

[0091] In another embodiment of the invention the arcuate shape may bebrought about by use of materials with temperature dependent shapememory such as the metal alloy Nitinol. The probe is fabricated to belinear at room temperature and arcuate at the temperature of thesurgical site. The temperature differential of the Nitenol at roomtemperature and at the surgical site may be increased by energydelivered to the probe, e.g. RF or resistive heating. Alternately theelectrical power may be directly applied directly to the Nitenol whichis itself a resistive element.

[0092] In another embodiment of the invention the arcuate shape may beinduced electrical activated expansion and contraction of materialswithin the probe. Piezo-electric crystals positioned on either theexterior or interior radius of the arc may be used in this manner torespectively expand or contract against a surface of a mandrel withinthe probe, to induce an arcuate shape.

[0093] In still another embodiment of the invention the alteration ofshape from linear to arcuate may be produced by mechanical means such asthe combination of a draw wire and mandrel, coupled at the tip of thedevice and extending the length of the catheter, such that tension ofthe draw wire induces tension on a side of the mandrel inducing it toassume an arcuate shape. Numerous combinations of material and energy,either thermal or electrical can be used to create a deformable tip.

[0094] An advantageous feature of all the probes set forth in thecurrent invention is that their shape can be configured to conform tothe interior shape of the surgical site to which they are introduced,thus placing functional elements on the probe into proximity with allportions of the surgical site without the need for a point-by-pointnavigation of the probe tip about the surgical site.

[0095]FIG. 3 shows an embodiment of a surgical catheter with a shapeshifting probe portion. The catheter 300 includes handle 306, stem 308probe section 316 and tip 320. The handle 306 at the proximal end of thecatheter is coupled via the stem 308 to the probe section 316, which islocated proximate the distal end of the device. At the terminus of theprobe, i.e., the distal end of the device, is the tip 320. In theembodiment show the probe is fabricated from a resilient material thusrequiring an introducer to effect its transition from a linear to anarcuate shape. In alternate embodiments any of the other activationelements described above could be utilized to effect a transition of theprobe section from a linear to a multi-dimensional shape.

[0096] FIGS. 4A-D show the sequence of operations associated with theinsertion of the probe section 316 of the catheter 300 shown in FIG. 3into the nucleus pulposus 120 of a spinal disc. In FIG. 4A the terminusof lumen 214 (See FIG. 2A) has been introduced into the nucleus pulposusof the disc substantially tangent to the interior sidewall of the disc.

[0097] In FIG. 4B handle and stem, respectively, 306-308 of the catheterare inserted further into the introducer 210 so that the tip 320 of theprobe section begins to extrude into the intradiscal space.

[0098] In FIGS. 4C-D the insertion continues until the probe section 316has formed a complete circle, with the tip 320 adjacent to the lumen 214of the introducer 210. In the embodiment shown, the plane defined by thearcuate probe is coplanar with the intradiscal plane defined by theintervertebral disc. Once the probe has deployed within the intradiscalcavity it may be further positioned by movement either of the introduceror the catheter. When the probe is properly deployed, functionalelements on the probe may be used to introduce heating or cooling of theintradiscal cavity or of selected portions thereof (See FIGS. 10A-B,11). In alternate embodiments of the invention the functional elementmay include a lumen for the introduction and/or removal of material intothe surgical site. (See FIGS. 12A-C). In still other embodiments in theinvention the probe tip may include a surgical knife, either alone or incombination with a lumen. (See FIGS. 12A-C).

[0099] To trace the location of a catheter probe within a surgical sitevarious imaging techniques may be used. A radiographically opaquemarking device can be included in the distal portion of the catheter(such as in the tip or at spaced locations throughout the probe portion)so that advancement and positioning of the probe section can be directlyobserved by radiographic imaging. Such radiographically opaque markingsare preferred when the probe section is not clearly visible byradiographic imaging, such as when the majority of the catheter is madeof plastic instead of metal. A radiographically opaque marking can beany of the known (or newly discovered) materials or devices withsignificant opacity. Examples include but are not limited to a steelmandrel sufficiently thick to be visible on fluoroscopy, atantalum/polyurethane tip, a gold-plated tip, bands of platinum,stainless steel or gold, soldered spots of gold and polymeric materialswith radiographically opaque filler such as barium sulfate. A resistiveheating element or an RF electrode(s) may provide sufficientradio-opacity in some embodiments to serve as a marking device.

[0100]FIG. 5 shows an alternate embodiment of the catheter with aninward spiraling probe portion. The catheter 500 has a handle 306coupled via stem 308 to the spiral probe section 516. The spiral probesection terminates at the distal end of the catheter in a tip 520.

[0101] As described and discussed above, the catheter may be cause toattain a spiral shape by numerous activation elements including the useof materials which are: resilient or bimetallic, which exhibittemperature dependent shape memory, by materials in which electricalexpansion and contraction may be induced, and by mechanical means. Apossible advantage of the inward spiraling shape is that material may beswept during deployment of the probe radially inward/outward.

[0102]FIG. 6A-B show respectively elevation and side views of analternate embodiment of a catheter with a catheter 600 with an outwardspiraling probe . Probe section 616 is coupled via stem 308 to handle306. Tip 620 is at the terminus of the Probe 616 at the end of thecatheter 600. As is evident in FIG. 6B the stem 308 intersects at anacute angle the plane defined by the spiral probe section 616. Suchalteration of the plane of the probe with respect to the stem may resultin improved conformity of the probe with the intradiscal cavity or otherjoint into which the probe may be introduced.

[0103] As described and discussed above, the catheter may be cause toattain a spiral shape by numerous activation elements including the useof materials which are: resilient or bimetallic, which exhibittemperature dependent shape memory, by materials in which electricalexpansion and contraction may be induced, and by mechanical means. Apossible advantage of the outward spiraling shape is that material maybe swept during deployment of the probe radially inward/outward.

[0104] The catheter 700 shown in FIG. 7-8 may be fabricated to deployinto either a planar two dimensional shape or into a three dimensional“eggbeater” shape which conforms to the surgical site. The catheterincludes a handle 706, a stem 708, a probe 702 and an introducer 210.The handle 706 includes a push/pull member 704. The stem 708 includes adraw member 730. The introducer 210 includes an internal lumen 214. Theprobe 702 includes side members 716 and a core member 732.

[0105] One or more of the side members 716 are arranged radially aboutcore member 732. The core extends axially and is attached at a distalend of the probe 702 to the distal ends of the side members by tip 720.At a proximal end the core joins with the draw member 730 as an axialextension thereof. The proximal ends of the side members 716 areslidably affixed to the draw member. Axially induced movement of theproximal ends of the side members along that draw member and toward thecore member 732 results in an arcuate deflection of the side membersfrom a collapsed position adjacent to the axial core to an expandedposition radially displaced about the axial core. The draw member 730extends axially the full length of the stem 708 and of the handle 706 toa point of attachment at the push/pull member 704 of the handle. Thedraw member is slidable axially within the stem. The push/pull member704 of the handle 706 is slidable axially with respect to the handle706.

[0106] In operation the side members 716 are brought into a lay-flatcondition against the axial core prior to introduction into theintroducer. This situation is brought about by the positioning ofpush-pull member adjacent to the handle 706. This causes the maximalextension of the draw member from a distal end of the stem 708. In anembodiment of the invention the lay-flat members are tension springs,which in the relaxed position lay flat against the axial core. In thislinear configuration, the tip 720 of the probe is placed into theintroducer 210. When the probe 702 is extended beyond the introducer andinto the surgical site, the draw member is gradually retracted into thehandle by a displacement of the push-pull member 704 away from the baseportion of the handle 706. This causes the distal end of the stem 708 topress the distal ends of the side members 716, thereby reducing theaxial distance between those members and the tip 720. As the distance isreduced, those members assume an arcuate shape radially displaced aboutthe axial core.

[0107] In an alternate embodiment of the invention, the side members ina relaxed position assume an arcuate shape radially displaced about theaxial core. By coupling the distal end of step 708 to the distal ends ofthe side member, an extension of the draw member resulting from movementof the push-pull member 704 toward the base portion of the handle 706causes the side members to lay flat against the axial core.

[0108] As described and discussed above, the catheter may be cause toattain the “eggbeater” or other shapes by numerous activation elementsincluding the use of materials which are: resilient or bimetallic, whichexhibit temperature dependent shape memory, by materials in whichelectrical expansion and contraction may be induced, and by mechanicalmeans.

[0109] An Electrophoretic Functional Element

[0110] The functional element of the probes shown in FIGS. 8A-F performan electrophoretic function with surgically beneficial results.Electrophoresis can be defined as the movement of charged particles orsubstances through a medium in which they are dispersed as a result ofchanges in electrical potential. For example, electrophoretic methodsare useful in the separating various molecular particles depending uponthe size and shape of the particle, the charge carried, the appliedcurrent and the resistance of the medium. In addition, with theappropriate construction of the anode (positive) and the cathode(negative) electrodes, the chemical milieu of a surgical site, e.g. thenucleus pulposus, can be altered by electrophoretic methods, withbeneficial therapeutic effects such as pain reduction or intradiscalrepair.

[0111] In a clinical setting, negatively charged ions or free radicalsmay be found in high concentrations in chronically inflamed states ofsurgical sites such as the intradiscal cavity of the spine. Disco-genicpain may for example be associated with higher than normalconcentrations of enzymes such as phospholipase A-2 in the spinal discwall, or the nucleus pulposus for example. Alternately, a recentlydiscovered short protein binds to cell membranes in the brain and spinalcord and may be affected and controlled by electrophoretic methods. Thepeptide, nocistatin, seemed to block pain or the transmission of pain tothe nociceptors or pain receptors when injected into animals. Nocistatinappears to interact with the peptide nociceptin in a manner which mayeither amplify or reduce pain depending on the relative concentrationsof the two peptides. Control of the these two peptides byelectrophoresis may prove beneficial in the treatment of back pain.

[0112] By inserting a probe into the site with a functional elementcapable of performing an electrophoretic function, it may be possible toreduce the concentrations of the charged particles: e.g. enzymes,neurotransmitters, proteins, individual molecules, or free radicals toachieve one or more beneficial therapeutic effects including but notlimited to pain reduction, intradiscal reshaping or repair.

[0113] The concentrations may be reduced by migration of the chargedparticles from perimeter regions of the surgical site toward the core ofthe site, by means of an appropriately configured probe, with electrodespositioned at the perimeter and core of the surgical site, whichelectrodes are charged in a manner designed to encourage whichever of aradially outward or inward migration of the charged particles istherapeutically beneficial.

[0114] In an embodiment of the invention, further beneficial effects maybe achieved when the charge on the probe is maintained as it iswithdrawn from the surgical site, thus encouraging the removal of thecharged particles from the site.

[0115] FIGS. 8A-F show multi-dimensional probes with side and coremembers deployed into a multi-dimensional configuration at the surgicalsite. The side and core members may perform an electrophoretic functionby means of electrical stimulus of opposite polarity applied to each.The electrical stimulus may be pure DC or rectified AC at frequenciesincluding the radio frequency range.

[0116] In FIG. 8A, side members 816 naturally assume an arcuateconfiguration radially displaced about core 832. They may be compressedagainst the core as is the case when they are within the lumen 214within the introducer 210. As they collectively extended through thelumen and into the surgical site their internal spring tension causesthem to assume an arcuate configuration radially displaced about thecore. At the completion of the surgery they may be withdrawn into thelumen, and in so doing, collapse against the core.

[0117] In an embodiment of the invention central core 832 providesstructural support to the tip of the probe. Additionally, central core832 is surrounded by membrane 833 which serves as a central collectorregion for the electrophoresis. In another embodiment of the inventionthe membrane 833 may itself serve as an electrode.

[0118] As described and discussed above, the catheter may be caused toattain the “eggbeater” or other shapes by numerous activation elementsincluding the use of materials which are: resilient or bimetallic, whichexhibit temperature dependent shape memory, by materials in whichelectrical expansion and contraction may be induced, and by mechanicalmeans.

[0119] Via electrical connections, the side members 816 and core 832 mayperform as electrodes. In an embodiment of the invention the sidemembers and core member are coupled to electrical power to serve asrespectively either anodes-cathode or cathodes-anode to one another. Theelectrical connections couple the electrodes to a source of power whichmay be located in the catheter or be externally coupled to theelectrodes through a coupling on the handle of the catheter. (See FIGS.13-14). This arrangement may have certain surgical benefits.

[0120] By allowing the side members and core to serve as respectivelyperimeter and core electrodes the core can be charged providing anelectrical gradient for electrophoresis to pull charged particles from aperimeter region in the disc to the core. The charge of the core 832electrode may be continuously maintained during collapse of the sidemembers and retraction of the probe from the surgical site, to removethe charged particles from the surgical site, e.g. the nucleus pulposus.This would effect a change to the nucleus pulposus and reduce theelectrical potential on the nociceptors, i.e. pain receptors, therebyreducing pain perception as well as removing material from the disc.

[0121] In another embodiment of the invention, electrically chargedparticles may be introduced into the intradiscal cavity by means ofmembrane 833. Upon deployment of the side members at the surgical site,and appropriate charging of the side and perimeter members the chargedparticles may be encouraged to migrate toward the side members therebyaffecting a change of the chemical milieu of the site.

[0122] FIGS. 8B-D shows demonstratively alternate functional embodimentsof the probe 820 deployed in relation to the intradiscal cavity whichcontains the nucleus pulposus 120.

[0123]FIG. 8B. shows one functional embodiment of the invention whereside structural members serve as a cathode 826 while central core servesas an anode 842. Under application of direct current, the negativelycharged particles are drawn toward anode 842.

[0124]FIG. 8C. shows probe 820 where side structural members serve asanode 842 while the core serves as cathode 826.

[0125]FIG. 8D. shows another embodiment where the core 832 is not anelectrode and side structural members serve as individual electrodes.Side structural members are each charged differently with one structuralmember serving as anode 826 and the other side structural member servingas cathode 832.

[0126]FIG. 8E shows an alternative embodiment of the functional aspectof probe 820 with additional intermediate side members 835. Intermediateside members 835 are, in a deployed state located radially between thecore and an associated one the side members. Intermediate side members835 are each electrically coupled to a corresponding one of side members816 by means of electrical connectors/ribs 825. The ribs create agreater electrical potential by increasing the electrode region. Theindividual ribs 825 may be constructed of the same material asintermediate side members 835 or any other electrically conductivematerial. The “fishrib” or fan-shaped structure of probe 820 in thisembodiment creates a greater driving force for changing the chemicalmilieu of the intradiscal cavity by electrophoretic means.

[0127]FIG. 8F is an embodiment whereby the greater electrical potentialis created by increasing the surface area of the electrode region by useof a film 822 with an electrically conductive layer, e.g. vacuummetalized polyester. The conductive layer may be continuous orpatterned. Opposing sides of the film are affixed to respective ones ofintermediate side members 837 and side members 816. As the tip isdeployed and expands to form an arcuate shape the film is deployed toexpose the electrically conductive layer. The electrical gradientcreated is similar to FIG. 8E where a greater driving force pushes thenegatively charged particles towards the central anode.

[0128] In another embodiment of the invention, the electrophoretic probemay be implemented utilizing a probe which, unlike the probes disclosedabove, is substantially linear in shape. In this embodiment,electrophoretic functionality is achieved by axially displacedelectrodes on the probe which are energized to opposing polarity toeffect a migration of charged particles from one electrode to the other,to achieve a beneficial therapeutic effect.

[0129] FIGS. 9A-D show the insertion stages of the catheter a surgicaljoint, in this case the intevertebral disc and specifically the nucleuspulposus 120 thereof. The device being inserted is the catheter 700shown in FIG. 7.

[0130]FIG. 9A shows the introducer 210 positioned so that the lumen atits distal end is within the intradiscal cavity. The stem 708 connectsthe handle 706 to the probe 702. The push-pull member 704 of the handle706 is in the inserted position proximate to the handle. In thatposition the draw member 730 (not shown) is fully extended and thecollapsible side members 716 lay flat against the axial core member 732within the intradiscal cavity.

[0131] FIGS. 9B-D show various stages of the expansion of collapsibleside members 716 radially about axial core member 732. This deploymentis brought about by the retraction of the draw member 730 (not shown)through stem 708 by means of the displacement of the push-pull member704 away from the handle 706.

[0132] Functional Elements

[0133] Since a purpose of the inventive catheter is to repair tears orfissures in a disc by operation of the instrument at the tear locationadjacent to or inside the disc, a functional element is provided in oron the catheter to carry out that purpose.

[0134] Non-limiting examples of functional elements include any elementcapable of aiding diagnosis, delivering energy, or delivering orremoving a material from a location adjacent the element's location inthe catheter, such as an opening in the catheter for delivery of a fluid(e.g., dissolved collagen to seal the fissure) or for suction, a thermalenergy delivery device (heat source), a mechanical grasping tool forremoving or depositing a solid, a cutting tool (which includes allsimilar operations, such as puncturing), a sensor for measurement of afunction (such as electrical resistance, temperature, or mechanicalstrength), or a functional element having a combination of thesefunctions.

[0135] The functional element can be at varied locations in the probeportion of the catheter, depending on its intended use. Multiplefunctional elements can be present, such as multiple functional elementsof different types (e.g., a heat source and a temperature sensor) ormultiple functional elements of the same type (e.g., multiple heatsources spaced along the probe portion).

[0136] One of the possible functional elements present on probe section216 is a thermal energy delivery device. A variety of different types ofthermal energy can be delivered including but not limited to resistiveheat, radio frequency (RF), coherent and incoherent light, microwave,ultrasound and liquid thermal jet energies. In one embodiment, thermalenergy delivery device is positioned proximal to the distal portion ofprobe section 216 so that there is no substantial delivery of energy atthe distal portion, which can then perform other functions without beingconstrained by being required to provide energy (or resist the resultingheat).

[0137] The energy directing device is configured to limit thermal and/orelectromagnetic energy delivery to a selected site of the disc and toleave other sections of the disc substantially unaffected. The energycan be directed to the walls of the fissure to cauterize granulationtissue and to shrink the collagen component of the annulus, while thenucleus is shielded from excess heat.

[0138] In various embodiments, catheter probe section 216 and/or tip 220are positionable to selected site(s) around and/or adjacent to innerwall of an annulus fibrosus for the delivery of therapeutic and/ordiagnostic agents including but not limited to, electromagnetic energy,electrolytic solutions, contrast media, pharmaceutical agents,disinfectants, collagens, cements, chemonucleolytic agents and thermalenergy. Probe section 216 is navigational and can reach the posterior,the posterior lateral, the posterior medial, anterior lateral, andanterior medial regions of the annulus fibrosus, as well as selectedsection(s) on or adjacent to inner wall of the nucleus pulposus 120.

[0139] In FIGS. 10A-B, 11, 12A-C embodiment of the catheter are shown inwhich the probe delivers thermal energy to reduce pain without ablationor removal of any disc material adjacent to and with or without removalof water vapor from the disc but without charring the nucleus. The probesection also can heat the collagen components of the annulus, therebyshrinking the annulus, with or without desiccating local tissue.

[0140] FIGS. 10A-B show alternate embodiments of a probe and tip, whichinclude a functional elements with the capability of delivering energyto the surgical site. In FIG. 10A, the functional elements exhibitscombined resistive and radio frequency energy delivery capability. InFIG. 10B, the device includes dual resistive heating capability.

[0141] In FIG. 10A, the distal portion of a probe 1000 is shown. Theprobe is tubular with an interior wall 1006. At the distal end of theprobe a tip 1002 is affixed to the probe. Within the interior of theprobe a resistive heating coil 1012 is positioned. The resistive heatingcoil is coupled via wires 1014 extending through the stem and handle toan energy delivery device 202 (see FIG. 2A). In the embodiment shown,the probe itself is electrically conductive, thus allowing for thedelivery of R.F. power to tip 1002 at the terminus of the probe 1000.The tip in combination with a return pad (not shown) affixed to thepatient, provides monopolar R.F. delivery to the surgical site. Toprevent R.F. power emanating from the exterior of the probe, an outersheath 1004, which is electrically insulating, is provided to surroundall except the terminus of probe 1000. To measure the temperature at thetip, a temperature sensing device 1018 is positioned inside the tip.That device is coupled via wires 1020 which extend the length of thestem to the handle to external controls for monitoring energy to thesurgical site. Heating coil 1012 may be powered by a direct currentsource (and less preferably a source of alternating current). Heatingcoil 1012 is made of a material that acts as a resistor. Suitablematerials include but are not limited to stainless steel, nickel/chromealloys, platinum, and the like. Preferably, the heating element isinside the probe. The resistive material is electrically insulated andsubstantially no current escapes into the body. With increasing levelsof current, the coils heat to greater temperature levels. In oneembodiment, 2 watts pass through heating element 46 to produce atemperature of about 55° C. in a selected target such as fissure, 3watts produces 65° C., 4 watts produces 75° C., and so on.

[0142]FIG. 10B shows an alternate embodiment of the energy deliveryelement. In this embodiment dual resistive/radio-frequency heat deliveryis provided. The probe 1050 defines an interior lumen portion in whichtip 1052 is placed. A short and long heating element, respectively1062-1068, are positioned around the exterior of the probe, and areconnected wires (not shown) to energy delivery device 202 (see FIG. 2A).To monitor the temperature of each of the coils thermo-couples 1070 and1072 are provided.

[0143] In another embodiment, radio frequency energy is delivered to theheating elements. As illustrated in FIG. 10B coils 1062, 1068 arepositioned on the exterior of probe 1050 and serve as RF electrodespowered by an RF generator. The electrodes are made of suitablematerials including but not limited to stainless steel or platinumIncreasing levels of current conducted into disc tissue heat that tissueto greater temperature levels. A circuit can be completed substantiallyentirely at probe section 16 (bipolar device) or by use of a secondelectrode attached to another portion of the patient's body (monopolardevice). In either case, a controllable delivery of RF energy isachieved.

[0144] In another embodiment sufficient energy is delivered to theintervertebral disc to heat and shrink the collagen component of theannulus but not ablate tissue adjacent to catheter 14. With a resistiveheating device, the amount of thermal energy delivered to the tissue isa function of (i) the amount of current passing through heating element,(ii) the length, shape, and/or size of the heating element, (iii) theresistive properties of the heating element, (iv) the gauge of heatingelement, and (v) the use of cooling fluid to control temperature. All ofthese factors can be varied individually or in combination to providethe desired level of heat. Energy delivery device 202 associated withthe heating element may be battery based. The catheters can besterilized and may be disposable.

[0145]FIG. 11 shows an alternate embodiment for the construction ofresistive heating coils. In the embodiment shown, a thin film resistiveelement, generally 1100, fabricated using technology derived fromprinted circuit boards, is provided. In this embodiment, the resistivewire 1106 is fabricated as part of a substrate or film 1 108, usingphoto-etch/engraving techniques. The substrate might for example be apolyester film. The wire may be internal to or deposited on a surface ofthe substrate. The coil can be fabricated on one side only of thesubstrate of film 1108, thus allowing for asymmetric delivery of heat.In assembly, the core can be positioned in the interior of the probe orheat shrunk around the exterior of the probe.

[0146] FIGS. 12A-C show an alternate embodiment of the invention inwhich a number of functional elements are provided, including aretractable blade, a lumen and a resistive heating element. FIG. 12Ashows an exterior side view of probe 1200. FIG. 12B shows a cross-sideview of the probe 1200. FIG. 12C shows a cross-sectional axial view fromthe probe interior facing the tip end of the probe.

[0147]FIG. 12A shows the probe 1200, generally tubular in shape, with anexterior tubular portion 1202. At the distal end of the probe a tip 1204is affixed. The tip defines in its face, a lumen 1206 in which thecutting tip of a retractable blade 1208 is shown in the retractedposition. In an embodiment of the invention, the exterior dimensions ofthe retractable blade are sufficiently less that the interior dimensionsof the lumen 1206 so as to allow for not only the retraction andextension of the blade, but also for either the removal by suction orintroduction by pressure of material from or to the surgical site.

[0148]FIG. 12B shows the cross-sectional view of the probe shown in FIG.12A. In addition to the features discussed above, the device is seen toinclude resistive heating coils 1210 contained within a spacing betweenthe exterior tubular portion 1202 and an interior tubular portion 1212of the probe 1200. The retractable blade is in turn slidably positionedwithin the interior tubular portion.

[0149]FIG. 12C shows a cross-sectional view facing toward the end ofprobe 1200. The exterior tubular portion 1202 and the interior tubularportion 1212 of the probe 1200 are shown. In the spacing between themthe resistive heating coils 1210 are shown. The blade 1208 is axiallypositioned within the inner tubular wall 1212.

[0150] The lumen 1206 may be configured to transport a variety ofdifferent mediums including but not limited to electrolytic solutions(such as normal saline), contrast media (such as Conray meglumineiothalamate), pharmaceutical agents, disinfectants, filling or bindingmaterials such as collagens or cements, chemonucleolytic agents and thelike, from the material delivery/removal device 204 (see FIG. 2A) to adesired location within the interior of a disc (i.e., the fissure).Further, the lumen can be used to remove nucleus material or excessliquid or gas (naturally present, present as the result of a liquefyingoperation, or present because of prior introduction) from the interiorof a disc. When used to transport a fluid for irrigation of the locationwithin the disc where some action is taking place (such as ablation,which generates waste materials), the lumen is sometimes referred to asan irrigation lumen. The lumen can be coupled to the materialdelivery/removal device 204 through the catheter. In addition to or insubstitution for the cutting blade, other instruments can be deliveredthrough the lumen including but not limited to: graspers, drill andbiopsy needle.

[0151]FIG. 13 shows a split interface generally 1300 for providingconnections on the handle of the catheter to join energy delivery andmaterial transfer elements within the probe 216 (See FIG. 2A) of thecatheter to material delivery/removal device 204 and energy deliverydevice 202 (see FIG. 2A). An electrical interface 1302, a luer interface1306 for fluids and an auxiliary interface 1304 are shown. The auxiliaryinterface could be utilized for a needle syringe, graspers or an opticalfiber for viewing a surgical site. As will be obvious to those skilledin the art, the probe may be configured for any one or all of thesefunctional elements.

[0152]FIG. 14 shows an integrated interface 1400 for providingconnections on the handle of the catheter to join energy delivery andmaterial transfer elements within the probe 216 (See FIG. 2A) of thecatheter to material delivery/removal device 204 and energy deliverydevice 202 (see FIG. 2A). Electrical interfaces generally 1402 and aluer interface 1404 for the introduction or removal of material to thesurgical site are shown. External threads 1406 are shown for couplingthe interface to material and energy delivery devices.

[0153] All publications, patent applications, and issued patentsmentioned in this application are hereby incorporated herein byreference in their entirety to the same extent as if each individualpublication, application, or patent was specifically and individuallyindicated to be incorporated in its entirety by reference.

[0154] All the disclosed embodiments of the invention described hereincan be realized and practiced without undue experimentation. Althoughthe best mode of carrying out the invention contemplated by theinventors is disclosed above, practice of the present invention is notlimited thereto. Accordingly, it will be appreciated by those skilled inthe art that the invention may be practiced otherwise than asspecifically described herein.

[0155] For example, the individual components need not be formed in thedisclosed shapes, or assembled in the disclosed configuration, but couldbe provided in virtually any shape, and assembled in virtually anyconfiguration. Further, the individual components need not be fabricatedfrom the disclosed materials, but could be fabricated from virtually anysuitable materials. Furthermore, all the disclosed elements and featuresof each disclosed embodiment can be combined with, or substituted for,the disclosed elements and features of every other disclosed embodimentexcept where such elements or features are mutually exclusive.

[0156] It will be manifest that various additions, modifications andrearrangements of the features of the present invention may be madewithout deviating from the spirit and scope of the underlying inventiveconcept. It is intended that the scope of the invention as defined bythe appended claims and their equivalents cover all such additions,modifications, and rearrangements. The appended claims are not to beinterpreted as including means-plus-function limitations, unless such alimitation is explicitly recited in a given claim using the phrase“means for.” Expedient embodiments of the invention are differentiatedby the appended subclaims.

What is claimed is:
 1. A catheter for delivering energy to anintervertebral disc, and said catheter including at a proximal end ahandle and at a distal end a probe and said intervertebral disc having anucleus pulposus, an annulus fibrosus, and an inner wall of said annulusfibrosus, said nucleus pulposus having a first diameter in a disc planebetween opposing sections of said inner wall, and said cathetercomprising: at least one energy delivery device located at the distalend of the catheter to deliver energy to portions of the intervertebraldisc; and an activation element located at the distal end of thecatheter, to transition the probe from a linear to a multi-dimensionalshape, within the intervertebral disc.
 2. The catheter of claim 1 ,wherein the activation element comprises: a resilient material which ina relaxed state effects an arcuate shape and which upon introduction ofexternal stress assumes a substantially linear shape.
 3. The catheter ofclaim 2 , further comprising: an introducer defining along alongitudinal axis a lumen dimensioned to apply external stress to theresilient material.
 4. The catheter of claim 1 , wherein the activationelement comprises: at least two materials exhibiting differentialcoefficients of thermal expansion and the at least two materials joinedto one another wherein at a first temperature the at least two materialsassume a substantially linear shape and at a second temperature the atleast two materials assume an arcuate shape.
 5. The catheter of claim 1, wherein the activation element comprises: a material with atemperature dependent shape memory wherein at a first temperature thematerial assumes a substantially linear shape and at a secondtemperature the material assumes an arcuate shape.
 6. The catheter ofclaim 5 , wherein the material comprises nickel-titanium.
 7. Thecatheter of claim 1 , wherein the activation element comprises: amandrel with a longitudinal axis, and the mandrel including adifferential bending ability in two orthogonal axis which are orthogonalto the longitudinal axis; and a piezo-electric material joined to themandrel along a length thereof, and the piezo-electric materialresponsive to an electrical stimulus to vary at least one dimensionthereof, to effect a transition of the mandrel from a substantiallylinear shape to an arcuate shape.
 8. The catheter of claim 1 , whereinthe activation element comprises: a mandrel with a longitudinal axis,and the mandrel including a differential bending ability in twoorthogonal axis which are orthogonal to the longitudinal axis; and atension member joined to the mandrel at a distal end thereof, andcoextensive with the longitudinal axis of the mandrel along a lengththereof, and the mandrel responsive to tension applied to the tensionmember, to effect a transition of the mandrel from a substantiallylinear shape to an arcuate shape.
 9. The catheter of claim 1 , whereinthe activation element comprises: at least two side members extendingaxially along a longitudinal axis of the probe and rigidly affixed atfirst ends thereof to the probe, and the at least two side membersmoveable from a first position proximate to the longitudinal axis of theprobe to a second position radially displaced about the longitudinalaxis of the probe.
 10. The catheter of claim 9 , wherein the at leasttwo side members comprise: a resilient material which in a relaxed stateeffects an arcuate shape and which upon introduction of external stressassumes a substantially linear shape.
 11. The catheter of claim 10 ,further comprising: an introducer defining along a longitudional axis alumen dimensioned to apply external stress to the resilient material.12. The catheter of claim 9 , wherein the at least two side memberscomprise: at least two materials exhibiting differential coefficients ofthermal expansion and at least two materials joined to one anotherwherein at a first temperature the at least two materials assume asubstantially linear shape and at a second temperature the at least twomaterials assume an arcuate shape.
 13. The catheter of claim 9 , whereinthe at least two side members comprise: a material with a temperaturedependent shape memory wherein at a first temperature the materialassumes a substantially linear shape and at a second temperature thematerial assumes an arcuate shape.
 14. The catheter of claim 13 ,wherein the material comprises nickel-titanium.
 15. The catheter ofclaim 9 , wherein the at least two side members comprise; a resilientmaterial which in a relaxed state effects a linear shape and which uponintroduction of a compressive force between the first ends of the atleast two side members and second ends thereof assumes a substantiallyarcuate shape; and a draw member coupled to the handle for applying thecompressive force to the resilient material, to effect a transition ofthe at least two side members from a substantially linear shape to anarcuate shape.
 16. The catheter of claim 15 , wherein the energydelivery element further comprises; a core parallel to the longitudinalaxis of the probe; and electrical couplings for applying electricalpower of an opposing polarity to respectively said at least two sidemembers and said core.
 17. The catheter of claim 1 , wherein the energydelivery element further comprises; at least one resistive coil locatedwithin the probe at a distal end thereof; and electrical couplings forapplying electrical power to said at least one resistive coil.
 18. Thecatheter of claim 1 , wherein the energy delivery element includes athermal energy delivery element.
 19. The catheter of claim 18 , whereinsaid thermal energy delivery element comprises at least one of aresistive heating element and at least one radio frequency electrode.20. The catheter of claim 18 , wherein the thermal energy deliveryelement comprises: a substrate fastened to the distal end of thecatheter; and a heating element fabricated on said substrate by aphoto-etching.
 21. A catheter for delivering energy to an intervertebraldisc, and said catheter including at a proximal end a handle and at adistal end a probe and the intervertebral disc having a nucleuspulposus, an annulus fibrosus, and an inner wall of said annulusfibrosus, said nucleus pulposus having a first diameter in a disc planebetween opposing sections of said inner wall, and said cathetercomprising: a substrate located at the distal end of the catheter; and aheating element adapted to deliver thermal energy to portions of theintervertebral disc, said heating element fabricated on said substrateby a photo-etching.
 22. The catheter of claim 21 , wherein the substratecomprises a polyester film.
 23. The catheter of claim 21 , wherein theheating element is asymmetrical fabricated on said substrate to deliverthermal energy asymmetrically to the portions of the intervertebraldisc.
 24. The catheter of claim 21 , wherein the substrate defines acylinder.
 25. A catheter for delivering energy to an intervertebraldisc, and said catheter including at a proximal end a handle and at adistal end a probe and the intervertebral disc having a nucleuspulposus, an annulus fibrosus, and an inner wall of said annulusfibrosus, said nucleus pulposus having a first diameter in a disc planebetween opposing sections of said inner wall, and said cathetercomprising: a first probe section defining along the length thereof afirst lumen; at least one energy delivery element located at the distalend of the catheter to deliver energy to portions of the intervertebraldisc; a tip coupled to the first probe section at a terminus thereof,the tip defining on an exterior face a second lumen substantiallyconcentric with said first lumen; and a blade positioned within thefirst lumen and extensible from a first position within said first probesection to a second position extending through the second lumen andbeyond the tip, to cut selected portions within the intervertebral disc.26. The catheter of claim 25 , further comprising: a second probesection defining along a length thereof a third lumen and the firstprobe section located within the third lumen, and the at least oneenergy delivery element located in an annulus defined between the secondand first probe sections.
 27. The catheter of claim 25 , wherein thefirst probe section couples with a material delivery source to removematerial from the intervertebral disc via the first and second lumens.28. The catheter of claim 25 , wherein the first probe section coupleswith a material delivery source to supply material to the intervertebraldisc via the first and second lumens.
 29. A catheter for deliveringenergy to an intervertebral disc, and said catheter including at aproximal end a handle and at a distal end a probe and saidintervertebral disc having a nucleus pulposus, an annulus fibrosus, andan inner wall of said annulus fibrosus, said nucleus pulposus having afirst diameter in a disc plane between opposing sections of said innerwall, and said catheter comprising: an energy delivery element locatedat the distal end of the catheter to deliver energy to portions of theintervertebral disc; a material transfer element located at the distalend of the catheter to transfer material to and from the intervertebraldisc; and at least one interface on the handle for coupling the energydelivery element and the material transfer element to external devicesfor energy and material transfer to and from the intervertebral disc.30. A method for deploying a probe portion of a catheter in amulti-dimensional shape within an intervetebral disc, and the catheterincluding at a proximal end a handle and at a distal end a probe and theintervertebral disc having a nucleus pulposus, an annulus fibrosus, andan inner wall of said annulus fibrosus, said nucleus pulposus having afirst diameter in a disc plane between opposing sections of said innerwall, and the method for deploying the probe portion comprising:configuring the probe of the catheter in a substantially linearconfiguration; applying a sufficient force to advance the probe of thecatheter through the nucleus pulposus, which force is insufficient topuncture the annulus fibrosus; deploying the probe in a substantiallyarcuate configuration within the inner wall of the annulus fibrosus, anddelivering energy from the probe to portions of the intervertebral disc.31. The method of claim 30 , wherein the deploying step is effectuatedby a resilient material which in a relaxed state effects thesubstantially arcuate configuration and which upon introduction ofexternal stress assume the substantially linear configuration.
 32. Themethod of claim 30 , wherein the deploying step is effectuated by atleast two materials exhibiting differential coefficients of thermalexpansion and the at least two materials joined to one another whereinat a first temperature the at least two materials assume thesubstantially linear configuration and at a second temperature the atleast two materials assume the substantially arcuate configuration. 33.The method of claim 30 , wherein the deploying step is effectuated by amaterial with a temperature dependent shape memory wherein at a firsttemperature the material assumes the substantially linear configurationand at a second temperature the material assumes the substantiallyarcuate configuration.
 34. A catheter for treating an intervertebraldisc, and said catheter including at a proximal end a handle and at adistal end a probe and said intervertebral disc having a nucleuspulposus, an annulus fibrosus, and an inner wall of said annulusfibrosus, said nucleus pulposus having a first diameter in a disc planebetween opposing sections of said inner wall, and said cathetercomprising: an electrophoretic element located at the distal end of thecatheter to alter the milieu within the intervertebral disc.